[Abstract Title]. - Society for Neuroscience

Authors: *K. M. NAUTIYAL 1 , A. C. RIBEIRO 2 , D. PFAFF 2 , R. SILVER 1 ;
1 Psyc, Columbia Univ., New York, NY; 2 Lab. of Neurobio. and Behavior, The Rockefeller
Univ., New York, NY
Abstract: There is increasing evidence of a bidirectional relationship between affect and the
immune system. Much of the work in behavioral neuroimmunology has focused on microglia as
the primary immune cell in an otherwise „immune-privileged‟ brain, however other cells
including mast cells, are also resident in the central nervous system. Although they are best
known for their role in allergy, broader functions of mast cells have recently been discovered.
Brain mast cells release cytokines and inflammatory agents as well as neuroactive mediators
including serotonin and histamine, implicated in the regulation of behavior (Silver et al, 1996).
Here we used two models to study the role of brain mast cells in the regulation of emotional
reactivity.
First, using the mast cell deficient Kit W-sh/W-sh “sash” mouse (which lacks all mast cells) we
measured behavior in the open field arena, elevated plus maze and cued fear paradigm. Sash
mice, compared to wild-type (WT) C57BL/6J and heterozygous littermate controls, showed
more anxiety-like and fearful phenotype. Physiologically sash mice were also more responsive to
stressors than controls, showing higher defecation rates (up to 4 times higher) and larger
increases in corticosterone (73.6 ng/ml more).
Second, using pharmacological blockade of mast cell degranulation with disodium cromoglycate
(cromolyn) injected into the brain and periphery, we explored how different populations of mast
cells impact anxiety-like behavior. Cromolyn injected centrally into the lateral ventricle of WT
mice increased anxiety-like responses in the open field arena (2 times longer latency to enter the
center) and elevated plus maze (6 times fewer open arm entries) compared to saline injected
controls. Interestingly, there were no behavioral differences between animals injected with saline
or cromolyn peripherally (i.p., cromolyn does not cross the blood brain barrier). The results
indicate that a lack of brain, rather than peripheral, mast cells underlies the differences in
emotional reactivity.
These data from genetic and pharmacological models taken together implicate brain mast cells in
the regulation of emotional reactivity and affect.
Disclosures: K.M. Nautiyal, None; R. Silver, None; D. Pfaff, None; A.C. Ribeiro, None.
Poster
280. Stress and the Brain: Stress and Neuroimmunology I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 280.4/NN4
Topic: E.06.c. Stress and neuroimmunology